Compensating propeller



April 29, 1924. 1,491,997

C. MESSICK COMPENSATING PROPELLEP.

' 2 Sheets-Sheet 1 Original Filed Feb. 5 1918 C. MESSICK COMPENSATINGPROPELLER April 29 1924. 1,491,997

inal Filed Feb. 5. 1918 2.5fieets-Sheet 2 Inventor Patented Apr. 29,1924.

CHARLES MESSICK, O F BEENTWOOD, NEW YORK.

oomrnnsarme raormna.

7 Application filed. February 5,1918, Serial No. 215,464. Renewed August2, 1928.

To all whom itmay concern:

Be it known that I, CHARLES MEssIoK, a citizen of the United States,residing at Brentwood, in the county of Suffolk and State of New York,have invented an Improvement in Compensating Propellers, of which thefollowing isa full, clear, and exact description.

' change the direction of its axis of rotation.

III. To compensate for and thus practically to overcome the degree ofvibration ordinarily transmitted from the pro eller (or propeller-likemember such as a tur ine) to its shaft and various other parts.

IV. To mount the rolieller upon the propeller shaft by a exi 1e couplingso constructed and arranged th'at, with the propeller in action, anychange in the direction of the axisof the propeller shaft will permitthe axis of the propeller to lag, cause the propeller blades to actdiflerentially upon the air and thus assist in reestablishing acoincidence of the two axes.

V. To so construct and arrange the proseller as to practically cause thepropeller,

uring its rotation, to automatically oppose or overcome various factorsotherwise tending to cause dynamic unbalance and dynamic thrustunbalance.

VI. To so construct and arrange the propeller as practically to.overcome or compensate for the gyroscopic efl'ect of the ropeller, in sofar as such gyroscopic e ect might otherwise resist a force tending tochange the direction peller shaft.

VII. To give the propeller such form and arrangement as to facilitate,in a general of the axis of. the proway, a change in the direction ofits axis of rotation.

VIII. To give the propeller such form and arrangement that when usedupon an aeroplane, any bodily turning movement of the aeroplane willcause the propeller blades to act difierentially upon the ad acent airin this diflerence in the density of air close to! such manner as tofacilitate said turning movement.

My invention may assume different forms and may be used in connectionwith pro-' pellers and turbines employed in different media and also inconnection with various revoluble members. To avoid' prolixity, however,I will show my invention as applied to a two-blade tractor propeller andalso as applied to a four-blade propeller, used upon aircraft.

For the purposes here contemplated, the two propellers shown are eachassumed to be in static balance.

In this connection it may be noted that i if a power-driven aeroplane,with a propeller mounted rigidly upon the propeller shaft, be turned inits flight, the rotation of the propeller causes each blade thereof todevelop dynamic unbalance twice during each rotation of the propellerupon its axis. This dynamic unbalance, together with' dynamic unbalancearising from othercauses, which is rendered manifest in the form ofundesirable vibrations, is compensated for by my device. y

It may be further noted that where a propeller is mounted rigidly uponthe propeller shaft of an aeroplane, as heretofore used, anotherundesirable condition arises. That is to say, the aeroplane has wingsextending horizontally and it has been found that as each propellerblade pames one of these Wings there is a distinct vibration. This is aparently due to the fact that each propeller blade, while in action,carries a ittle volume of compressed air upon its rearward face, and apartial vacuum close to its forward face; and as a consequence of theblade, each pasage of the blade into and out of proximity to any wing orother ob 'ect sets 11 the vibration just mentioned. y inventlon tends toreduce this fault.

An aeroplane when in other than straight flight is deflected from normalresponse to the controls by gyrosco ic precession of the rotating parts,particu arly by the rotating mass of the propeller and my inventiontends to permit normal response to the controls by preventin thegyroscopic precession of the pro el er being transmitted to. the shaftand t rough it to the aeroplane.

Reference is made to the accompanying drawings forming a part of thisepecification, and in' which like letters indicate like parts throughoutthe several views.

Figure 1 is a fragmentary side elevation of a two-blade propeller madein accordance with my invention, and shows the variousparts in normalposition as they appear with the machine moving to the right propellerand differs from Figure 1 in that it shows the propeller blades asrocked from normal position, as hereinafter more completely described.

Figure '4 is an inverted plan. or bottom view, of the propeller shown inFigure 3.

Figure 5 is a fragmentary front elevation, showing a four-bladepropeller equlpped with my invention.

Figure 6 is a section on the line. 6-- 6' of Figure 5, looking in thedirection indicated by the arrows.

Figure 7 is a side elevatlon of one of the gimbals of Figures 5 and 6.

Figure 8 is an end elevation of the gimbal shown in Figure 7.

Figure 9 is a fragmentary side elevation of the propeller shaft ofFigures 5 and '6.

Referring to Figures 1 to 4, lncluslve, a propeller shaft 10 carries ahub 1 1, secured rigidly upon it and having 1n this lnstance the form ofa fork.

Located within this fork and ]ourna led relatively thereto by a pin 12is a rocking hub 13, carrying a pair of propeller blades 14, 15, eachextending in a general direction oblique to the length of the pin 12, asshown in Figure 2.

The direction of rotation of the propeller and its shaft is indicated bycurved arrows, the air stream being indicated in Figures 1 and 3 bystraight arrows.

This is a tractor propeller-that 1s, one

i which pulls rather than pushes-and the direction of travel of theaeroplane is to the right according to Figures 1. 3 and. 4.

Referring more particularly to Figure 2, it will be noted that the pivotpin 12 extends through the hub of the propeller at an angle ofapproximately 45 degrees relatively to the length of the propellerblades,

and that the propeller blades, though rigid relatively to the hub andeach other, are as a unit free to rock on the swivel pin. It will alsobe noted that when the blades thus rock. the pitch of the rearward bladeincreases as that of the \forward blade de ferentially upon the air andtend to reestablish the blades 14 and 15 in perpendicular relation toshaft 10. lVhen the propeller rotates 180 degrees blade 15 assumes theindicated position of blade 14 and blade 14 that of blade 15. At someintermediate point both blades become momentarily perpendicular to shaft10, thus each blade thrusts the air with more than its normal pitchduring half a complete revolution and less than normal pitch during theother half revolution, so that the unbalanced air thrust between theblades tends twice in each revolution to reestablish them inperpendicular relation to shaft 10.

In some cases, where this variable pitch is found undesirable, the angleof the pivot pin with relation to the length of the blades may be madedegrees or more to meet such requirements as develop with the progressof the art.

In Figures 3 and 4, the propeller is shown in a slightly differentposition with relation to the axis of the shaft, indicating the changeof pitch in the blades (14 and 15) with relation to the shaft which hasautomatically occurred as a result of the rocking of the propeller onthe swivel pin (12). Thisincrease in pitch of blade 14 causes anincreased air thrust to be delivered by it and the pitch and air thrustof'blade 15 are decreased. which tends to' return the propeller to thenormal plane perpendicular to the shaft 10, as indicated in Figures 1and 2. i

The movement of the blades from the position indicated in Figures 1 and2 to the position indicated in Figures 3 and 4 may be caused byinequality of air thrust on the blades, gyroscopic effect of thepropeller tending to resist the turning of the aeroplane. or by otherfactors of dynamic unbalance. which may arise in operation; but thetendency is always for automatic compensation to be provided by thedevice, so

-that the axis of the propeller and the axis shaft. The air thrust ofthe two blades collectively is approximately constant and operatesperpendicular to the length of the blades and. as their position withrelation to the shaft is only momentarily distorted from theperpendicular, the air thrust is communicated to the shaft constantlyand but little vibration due to dynamic unbalance is imposed upon it. 7

In the form of my device shown in Fi ures 5 to 9 inclusive the propellersha creases. This causes the blades to act difappears at 16, and has atubular. form. It

is mounted in bearings 17, encloses the barrel of a gun 18, and the axisof the gun coinciding with the axis of the shaft in the usual manner.

Secured rigidly upon the tubular shaft 16 is a collar 19, carrying apair of trunnions 21, each trunnion having a shoulder 20. The tubularshaft 16 extends through a gimbal ring 22, the trunnions 21 extenda whenthe axes of the propeller and the propeller shaft are forced outofcoincidence by movements of the aeroplane or air, they are restored tocoincidence by the wellknown laws governing the'movements of a fly-wheeldriven by shaft. The pitch of the blades is constant in the four bladedtype.

When the propeller is in action, any general turning movement 'of theaeroplane during its manoeuvres tends to cause the propeller to lagbehind, as it were, but owing to the flexible coupling and thecentrifugal force and the reaction of the air upon the propeller, it isgradually shifted around until it becomes normal to the axis of thepropeller shaft. In other words the lagging of the propeller is onlymomentary, and the propeller quickly turns bodily around and faces thenew direction 111 which the aeroplane is then traveling. The momentarylag, however, avoids the necessity for a positively-driven turn of thepropeller corresponding to the turning movement of the aeroplane, andthis momentary lag afi'ords relief to the propeller shaft and itssupports.

I do not limit myself to the preclse construction shown, the scope of myinvention being commensurate with my claims.

I claim 1. The combination of a propeller shaft, a propeller balancedthereon and driven thereby, and a flexible coupling to transmit torqueand thrust only between the shaft and the propeller.

2. The combination of a propeller shaft, 9. ropeller balanced thereonand driven therey, and a coupling for the shaftand the propellerdesigned'to transmit torque and thrust only whereby dynamic vibrationsarising in the propeller may be insulated from the shaft.

3. In a device-of the character described, the combination of apropeller shaft, a propeller provided with blades and mechanismconnectingsaid propeller and shaft for compensating dynamic unbalancebetween the blades. c

4. In a device of the character described, the combination of apropeller shaft, a propeller provided with blades and mechanismconnecting said propeller and shaft for compensating dynamic thrustunbalance between the blades.

A device of the character described comprising a propeller shaft, apropeller, and mechanism so connecting said propeller shaft and saidpropeller as to balance the thrust of the propeller against thegyroscopic effect thereof whenever the axis of the propeller shaft ischanged in direction.

6. A device of the character described, comprising a propeller shaft, apropeller, and mechanism so connecting the propeller shaft and thepropeller as to compensate for gyroscopicretardation of said propellerby fluid thrust when the axis of rotation of said shaft is changed indirection.

7. A device of the character described, comprising a revoluble propellershaft and a propeller provided with blades carried thereby, saidpropeller being free to rock on an axis crossing the axis of thepropeller shaft, and so arranged that the pitch of each blade is changedby the rocking of said propeller. V i I 8. A device of the characterdescribed, comprising a revoluble propeller shaft, a propeller providedwith blades carried thereby and a flexible connection to enable saidpropeller to rock on an axis crossing the axis of the shaft to cushionvibration and balance gyroscopic efi'ect against fluid thrust when thedirection of the axis of the shaft is changed.

9.'A device of the character described, comprising a propeller shaft anda pair of propeller blades carried thereby, said blades being free torock lengthwise of the shaft and having variable pitch controllable bythis rocking movement of said blade's,.said propeller blades being soconnected that an increase in the pitch of one blade is accompanied by adiminution in the pitch of the other blade.

10. A revoluble shaft and a propeller mounted thereon and provided witha hub and with blades carried by said hub and extending therefrom inorder to'balance eachother, said blades beingrevoluble with the shaftand journaled to rock upon an axis crossing the general direction inwhich the blades extend.

-11. A revoluble shaft and a propeller mounted thereon and provided witha pair of blades balancing each other and extending in oppositedirections, the blades'as a unit being rigid relatively to each otherand revoluble with the shaft, and journaled to rock upon an axiscrossing the general direction of the length of the blades.

12. The combination of a revoluble shaft and a pair of propeller bladescarried thereby and extending therefrom in opposite directions, saidblades being rigid relatively to each other and as a unit journaled torock upon an axis extending oblique to the length of the blades. 7

13. The combination of a revoluble shaft and a propeller carried by saidshaft and extending radially therefrom, said propeller being journaledto rock upon an axis oblique to the length of the propeller and crossingthe general axis of the l'evoluble shaft.

14. The combination of a revoluble shaft and a propeller carried by saidshaft and extending radially therefrom, said propeller being journaledto rock upon an axis cross- 20 ing at right angles the general axis ofthe revoluble shaft but inclined obliquely to the length of theropeller.

15. The com liination of a revoluble shaft carrying a pair of propellerblades extending radially therefrom in opposite directions in order tobalance each other, said blades being revoluble bodily with said shaftand journaled to rock upon a single axis crossing at right angles thegeneral axis of the revoluble shaft and at all times inclined relativelyto the common length of the blades.

16. A revoluble shaft, a member designed for high peripheral speeds,whereby gyroscope efiects-of great magnitude may be developed and aflexible coupling at the center of the member and at the shaft, wherebythe axes of the shaft and member may be more easily moved out ofcoincidence at high speeds than if rigidly coupled together.

CHARLES MESSICK.

